Voltage conversion control device for motor

Abstract

Disclosed is a control device which performs voltage conversion control for a voltage conversion circuit between motor control circuits which control a plurality of motors and a power supply. The control device includes sampling means for sampling a DC voltage after voltage conversion, target voltage setting means for setting target voltages of the plurality of motors, selection means for selecting a target voltage to be converted by the voltage conversion circuit from among the plurality of target voltages, generation means for generating a sampling timing on the basis of a carrier signal of one of the motors having the unselected target voltage, and control means for performing voltage conversion control using the DC voltage sampled by the sampling means in response to the sampling timing for each sampling timing request of voltage conversion control.

The invention claimed is: 
     
       1. A voltage conversion control device for a motor which performs voltage conversion control on a voltage conversion circuit provided between a motor control circuit controlling a plurality of motors and a power supply, the voltage conversion circuit configured to convert a DC voltage of the power supply to an input DC voltage necessary for driving the motor, the voltage conversion control device comprising:
 sampling unit that detects a voltage across both ends of a capacitor provided between the motor control circuit and the voltage conversion circuit and sampling the input DC voltage converted by the voltage conversion circuit; 
 target voltage setting unit that sets a target voltage of the input DC voltage for each motor; 
 selection unit that selects a target voltage to be converted by the voltage conversion circuit from among a plurality of target voltages set by the target voltage setting unit; 
 sampling timing generation unit that generates a sampling timing of sampling the input DC voltage converted by the voltage conversion circuit on the basis of a carrier signal of motor control on one of the motors having the target voltages not selected by the selection unit; and 
 control unit that performs voltage conversion control using the input DC voltage sampled by the sampling unit in accordance with the sampling timing generated by the sampling timing generation unit for each sampling timing request of the voltage conversion control. 
 
     
     
       2. The voltage conversion control device for a motor according to  claim 1 ,
 wherein the sampling timing generation unit generates a sampling timing in response to a crest and a trough of the carrier signal, each time the sampling timing is generated, the input DC voltage converted by the voltage conversion circuit is sampled by the sampling unit, and for each sampling timing request, the control unit performs the voltage conversion control using the input DC voltage sampled in accordance with the sampling timing immediately before the sampling timing request. 
 
     
     
       3. The voltage conversion control device for a motor according to  claim 1 ,
 wherein, for each sampling timing request, the sampling timing generation unit generates a sampling timing in response to a crest or a trough of the carrier signal immediately after the sampling timing request, the sampling unit samples an input DC voltage converted by the voltage conversion circuit in response to the sampling timing, and the control unit performs voltage conversion control using the input DC voltage sampled in response to the sampling timing for each sampling timing request. 
 
     
     
       4. The voltage conversion control device for a motor according to  claim 1 ,
 wherein the plurality of motors are two motors, 
 the target voltage setting unit sets the target voltages of the two motors, 
 the selection unit selects a target voltage to be converted by the voltage conversion circuit from among the target voltages of the two motors set by the target voltage setting unit, and 
 the sampling timing generation unit generates a sampling timing for sampling an input DC voltage converted by the voltage conversion circuit on the basis of a carrier signal of the motor having the target voltage not selected by the selection unit.